I'm a bit late, but your performance issue could be caused by just using one of your CPU cores. My laptop has an Intel Core2Duo with 2.5GHz, and I wasn't pleased with the performance, too. Then someone told me that Race07 is using only one core of the CPU, but can use two.
To use two cores you have to start the game, then press Ctrl+Shift+ESC to start the Task-Manager, rightclick on race07.exe, click on "Set Affinity..." and then unselect one core and press OK. After this rightclick on race07.exe again, click again on "Set Affinity..." and select the core again, so that every core is "allowed to run the program" and press OK.
After this Race07 should use two cores, what will give you a performance boost, if your performance was limited by just using one core. If it was limited by the GPU it won't help you.
You have to do this after every start of the game.